Color discharge printing



Patented June 28, 1932 UNITED STATES PATENT OFFICE FREDERICK R. BYROD, F SUNBURY, PENNSYLVANIA, ASSIGNOR TO SUSQUEHANNA SILK MILLS, A CORPORATION OF NEW YORK J COLOR DISCHARGE PRINTING No Drawing.

The present invention relates to a process of color discharge printing and to the colored discharge printing pastes employed therein. The process is applicable to any tex- Ll tile fabric, whether of animal or vegetable origin. It is particularly suitable for silk and rayon fabrics.

It has hitherto been customary to prepare colored discharges by printing a fabric which has been dyed with a reducible ground color by means of a paste comprised of a reducing agent, such as hydrosulfite, formaldehydesulfoxylate, or other combinations of hydrosulfite and formaldehyde, etc., a coloring matter which is unaffected by the reducing agentand one of the usual thickeners, such as gums, dextrines and the like. The reducing agents are found on the market under various trade names, such as Rongalite, Discolite, Sulfoxite and Hydrosulphite, A. W. .C.

This process was not fully satisfactory because when printing medium and pastel shade intensities is attempted, the resultant shade on silk, rayon and the like has a tendency to show a Washed out character, sometimes changing in cast or color, as, for instance, from a luminous medium blue to a washed out greenish blue. There is also the difficulty of unevenness in so far as given surfaces have a tendency to show white rings around the area where the colored mixture of reducing agent thickener and unreducible dye has been applied. Sometimes a mottled or speckled appearance develops. Again there exists the constant risk of irregularity of developing finely fixed tones in the aging process, which, in many cases, causes the same coloring matter made with identical formulas to appear in successive printings either dark, medium or sometimes so light that for all practical purposes it has disappeared. The latter efiect has never been definitely accounted for, but it is' commonly known that it is as good as impossible to keep :1 definite cast of color on silk which passes through the aging process.

I have found that these disadvantages can almost completely be avoided in a very simple manner. According to my new process a substantial amount of finely divided tita- Serial No. 580,224.

nium dioxide is added to thecoloreddischarge paste. The titanium dioxide, thus added, may serve to replace part of the thickening agent formerly used in the preparation of the colored discharge paste. ,The essential constituents of my improved colored discharge paste are a reducing agent, such as hydrosulfite, f0rmaldehyde-sulfoxylate, or other combinations of hydrosulfite and formaldehyde and the like, a coloring matter which is unaffected, i. e., not reduced, by the reducing agent and titanium dioxide. Further additions, such as are customary in the preparation of printing paste, may also be present, such as thickeners, glycerine, etc. One may substitute zinc oxide for part of the titanium dioxide, and this will in most cases be advisable, owing to the higher cost of the titanium dioxide. However, the quality of the colored prints obtained is improved by the use of a greater proportion of the titanium dioxide and, therefore, a substantial amount thereof is always used in the preparation of my improved colored dischar pastes. The titanium dioxide present in t e colored discharge pastes has a delustering "effect on rayon, which makes the color stand out. Thus, the quality of the colored prints obtained is improved by the delustering effect of the titanium dioxide present and the possibility of mechanical defects during the printing process is strongly reduced by the presence of a substantial proportion of titanium dioxide in the colored discharge paste.

The amount of the titanium dioxide, or mixture of titanium dioxide and zinc oxide, present in the colored discharge paste may vary within wide limits. Preferably it will constitute from 3 percent to 24 percent by weight of the colored discharge paste.

The particular coloring matters suitable for use in the process can readily be selected hv those skilled in the art. As has been pointed out above. the ground color should consist of a dischargeable, i. e., reducible, dyestuff, whereas the coloring matter contained in the colored discharge paste should consist of the dyestufi which is unaffected, i. e. not

following may be mentioned: 5

Discha/rgeable ground colors DIRECT COLORS Rowe's Name 01 color Color In gg dex No.

Amanil blue 28 406 337 Chloramlne red 3B 382 319 Direct black. 581 462 Direct blue 3B 477 391 Direct green B 593 474 Direct sky blue FR 518 424 Erie fast brown GR 598 477 Erie fast scarlet YA" 326 279 Fast acid green B 667 503 Trlazol yellow G 365 304 DEVELOPED COLORS Diazamine blue BR 316 273 Diazo black BH 401 333 Diazo fast green BL 532 Dlazol fast violet NN 394 327 Diazo indigo blue B 316 273 Plutoforrn black L 545 Rosanthrene O 324a N on-dzschargeable prmt colors BASIC COLORS Euchrysine RDX 797 608 Methylene blue B 922 659 N igrosine water solub 865 700 Nile blue B 914 654 Phosphine 0 Ex 793 606 Rhodamine B Ex 749 573 Rhodamine 6G Ex. 752 571 Rhoduline blue GO 926 001 Safranine A 841 679 Thioflavine T 815 618 ACID COLORS Azo carmine GX 828' 672 VAT COLORS Algol scarlet G 1129 815 Anthrene jade green. 1101 Ciba orange G 1230 911 Clba scarlet G Dbl. paste pa 1228 907 Indenthrene black 13 1102 765 Indanthrene blue GOD Dbl. paste" 1113 S42 Indzmthrene yellow G Dbl. paste 1118 849 The following are examples of discharge pastes to which the unreducible printing color may beadded (parts by weight) The discharge printing process is carried out in the usual manner. The textile material, for example, a silk or rayon fabric, is first dyed with the reducible ground color. It is then printed in the usual manner with the colored discharge paste. Thereupon the material is developed, for example, by steaming in a Mather-Flatt apparatus, and finally washed and soaped.

Obviously my invention is not limited to the particular examples given above. As has already been pointed out, the crux of my invention resides in the use of titanium dioxide as one of the constituents of the colored discharge paste used.

I claim:

1. A process of obtaining colored discharges on textile materials which have been dyed with a dischargeable ground color which comprises printing said materials with a colored discharge paste containing a re-.

ducing agent, an unreducible coloring matter and titanium dioxide.

2. A process of obtaining colored discharges on textile materials which have been dyed with a dischargeable ground color which comprises printing said materials with a colored discharge paste containing a reducing agent of the group consisting of hydrosulfite, formaldehyde-sulfoxylate and other combinations of hydrosulfite and formaldehyde, an unreducible coloring matter and from 3 percent to 24 percent by weight of titanium dioxide.

8. A process of obtaining colored discharges on textile materials which have been dyed with a dischargeable ground color which comprises printing said materials with a colored discharge paste containing a reducing agent, an unreducible coloring matter, titanium dioxide and zinc oxide.

. l M Malta Malamute 4. A process of obtaining colored discharges on textile materials which have been dyed with a dischargeable ground color which comprises printing said materials with a colored discharge paste containing a reducing agent of the group consisting of hydrosulfite, formaldehyde-sulfoxylate and other combinations of hydrosulfite and formaldehyde, an unreducible colorin matter and from 3 percent to 24 percent y weight of titanium dioxide and zinc oxide.

5. A process of obtaining colored discharges on silk fabrics which have been dyed with a dischargeable ground color which comprises printing said fabrics with a colored discharge paste containing hydrosulfite, a dyestuif which is not reduced by the hydrosulfite, and from 3 percent to 24 percent by weight of titanium dioxide and zinc oxide,

developing said fabrics by steaming and then washing and soaping the fabrics.

6. A colored discharge paste which comprises a reducing agent and unreducible coloring matter and titanium dioxide.

7. A colored discharge paste which comprises a reducing agent of the group consisting of hydrosulfite, formaldehye-sulfoxylate and other combinations of hydrosulfite and formaldehyde, an unreducible coloring matter and from '3 percent to 24 percent by weight of titanium dioxide.

8. A colored discharge paste which comprises a reducing agent, an un'reducible coloring matter, titanium dioxide and zinc oxide.

9. A colored discharge paste which comprises a reducing agent of the group consisting of hydrosulfite, formaldehye-sulfoxylate and other combinations of hydrosulfite and formaldehyde, an unreducible coloring matter and from 3 percent to 24 percent by weight of titanium dioxide and zinc oxide.

10. A colored discharge paste which comcent to 24 percent by weight of titanium dioxide and zinc oxide.

In testimony whereof I have hereunto set my hand.

FREDERICK R. BYROD. 

